Reservoir-buffered mixers and remote valve switching for microfluidic devices

Abstract

The present invention relates generally to the control of fluid flow rate and direction on a microfluidic device. In particular, the present invention provides an integrated valveless microfluidic device, where directional fluid control is controlled using off-chip remote valve switching and fluid flow rate changes are controlled using on-chip flow-rate changing fluid reservoirs. The present invention provides methods and systems for directional fluid control and control of fluid flow rate in an integrated microfluidic device which enables processes with different flow rates to be performed on one device without the need of on-chip valves.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority under 35 U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No. 61 / 164,756 filed Mar. 30, 2009, the contents of which are incorporated herein by reference in their entirety.FIELD OF THE INVENTION[0002]The present invention generally relates to the field of microfluidic devices, and in particular integrated microfluidic devices and the control of the movement of fluid within microfluidic devices. In particular, the present invention relates to methods, devices, systems and instruments for directional fluid control and rate of fluid control, using remote valve switching devices and systems and reservoir buffered devices and systems respectively.BACKGROUND OF THE INVENTION[0003]Currently, the majority of infection diagnoses, e.g. bacterial, parasites, fungi, viruses are conducted via cultures2 or immunoassays or PCR (e.g. viruses), which can take many hours to days. Thus, physicians will typically pres...

AI Technical Summary

Benefits of technology

[0019]One advantage of the microfluidic chips comprising flow-rate and / or velocity changing fluid reservoirs is that they have a very low-cost of manufacture due to lack of on-chip valves, and also enables multiple processes using different flow velocities to be performed on a single microfluidic chip. Thus, microfluidic chips comprising and / or velocity changing fluid reservoirs are particularly suited for use as single-use, fully-integrated disposable chips for complete sample processing and analysis in a high throughput manner.

[0020]In particular, in order to achieve a truly low-cost integrated disposable microfluidic chips, in which fluid flow can be regulated in an automated manner, the inventors have minimized the cost of the disposable component by removing all active components from the chip, enabling the chip to have a planar design and to be manufactured using low-cost methods such as injection molding, where a minimal number of assembly steps are required. Additionally, the inventors have used material with dimensional stability at high temperatures (unlike PDMS) and that could be manufactured reproducibly without caustic chemicals (such as hydrofluoric acid which is used to etch glass). In alternative embodiments, one can make the disposable microfluidic chip from any suitable material known by persons of ordinary skill in the art, for example, but not limited to plastics (e.g. acrylic, polycarbonate, etc) and other cheap, durable stable synthetic materials where thermal stability and / or on-chip fluorescence detection is not important.

Problems solved by technology

Even where the microfluidic devices are fluidly connected to each other, the transfer of the sample between the microfluidic devices can increase risk of sample contamination and loss of sample volume.

However, existing microfluidic devices and lab-on-a-chip which comprise multiple modules which require different velocities are highly complicated devices, often comprising on-chip valves, multiple layers and multi-level structures, multiple material types and a number of assembly steps required.

The presence of on-chip valves and multiple layers on microfluidic chips results in very expensive manufacturing costs not suitable for a cheap-disposable lab-on-a-chip system.

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